Does anyone know if the different poled versions of Speakon connectors are compatible? IE, can I have an 8 pole Speakon cup at the back of my amp with 4 channels hooked up to it, and use a 2 channel, 4 pole connector (just using two of the 4 amplifiers)?

AFAIK (but I'm not sure), the 2- and 4-channel versions are compatible, but the 8-channel plug is larger and will not fit in a 2-or 4 pole socket. Hvae you checked Neutrik's site for information of this? (the mechanical drawings will confirm if I'm right )